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A303544 Numbers k that divide primepi(k)^prime(k). 1

%I #16 Jul 11 2021 02:29:02

%S 1,4,8,16,27,64,96,120,125,169,189,256,324,350,605,729,864,896,1008,

%T 1024,1080,1116,1296,1375,1444,2187,2209,2268,2304,2349,2401,2430,

%U 2888,3087,3125,3328,3645,3698,4000,4096,4356,4394,5184,6480,8192,8464,10648

%N Numbers k that divide primepi(k)^prime(k).

%C Except for 1, terms are not squarefree, that is, all terms > 1 form a subsequence of A013929.

%H Chai Wah Wu, <a href="/A303544/b303544.txt">Table of n, a(n) for n = 1..500</a>

%F Numbers k such that the set of prime factors of k is a subset of the set of prime factors of primepi(k).

%t Select[Range[2^14], PowerMod[PrimePi[#], Prime[#], #] == 0 &] (* _Michael De Vlieger_, May 14 2018 *)

%o (PARI) isok(n) = !(primepi(n)^prime(n) % n); \\ _Michel Marcus_, May 14 2018

%Y Cf. A013929, A109710.

%K nonn

%O 1,2

%A _Chai Wah Wu_, Apr 25 2018

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Last modified April 18 16:22 EDT 2024. Contains 371780 sequences. (Running on oeis4.)